I'm getting ready to pull the fuel rail to replace the hoses, and while looking at the rail today I noticed that the vacuum hose that looks to have been attached to the fuel rail via the brown "switch" had, at some time, broken off.

What is this device, and is it worth replacing? The engine doesn't seem to notice that it's no longer attached.

Thanks,

John
1987 XJS V12, 62,000 miles

 

It is a pad type temp sensor for fuel temp in the rail after shutdown.

The HE had HUGE issues with hot restart in some markets.

If the car is all "warm and fuzzy" with it out of the system, leave it be, do not tempt fate in MY opinion.

They are probably still available, not cheap I reckon.